package demo1;

import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

public class Test {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        Set<Character> set = new TreeSet<>();
        StringBuilder stringBuilder = new StringBuilder();
        String s = "asd";
        s.contains("asdf");
        s.contains("a");
    }
}
